IAQA 2009 Annual Conference Ft. Worth
How “Green” is your Cordless Phone
HOW “GREEN” IS YOUR CORDLESS PHONE?
RF RADIATION REVIEW
WHAT DOES GREEN MEAN?
The term “green” is the magic word of today and is being use ubiquitously with many
products and processes for the indoor environment. But want does a “green” building
actually mean and entail? Do we mean?
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•
•
•
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Natural materials
Non-toxic materials
Sustainable materials
Energy efficiency
Recycled materials
Low emission materials
Low carbon foot print
Most of us are familiar with indoor environmental quality. But does that also include low
EMF and RF environments? This presentation will provide an insight on how a small
common household item can have a major impact on our electromagnetic environment
inside our buildings. We will review some low emitting or “green” devices which are
available.
DECT TECHNOLOGY HAS FINALLY REACHED US SHORES
Beginning last year, phones of the DECT 6.0 generation
started flooding the US market. DECT is the abbreviation
for Digital Enhanced Cordless Telecommunication
technology. In the last decade, only Europeans used this
technology and were confronted with its headaches.
The 2.4 GHz band has been used by the majority of
cordless phones in the last five years. However, this band
has become crowded with devices such as microwave
ovens, wireless area networks (WLAN), Bluetooth,
cordless phones and remote control devices. This has led
to interference and performance issues so the
manufacturers have moved to the 5.8GHz frequency band
and the DECT 6.0 technology.
The problem with the DECT phones is that the base station is permanently sending
(radiating), 24 hours a day, no matter if the system is in use or not. Indoor
environmental consultants have rallied against their use for decades. There were so
many outcries that it had an impact. Major European manufacturers now offer
environmental safer versions, with sleep mode or reduced output in stand by mode.
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IAQA 2009 Annual Conference Ft. Worth
How “Green” is your Cordless Phone
REGULATORY STANDARDS
Regulatory maximum exposure limits are set by the FCC (Federal Communication
Commission) for cellular providers and OSHA (Occupational Health and Safety
Administration) for employee workplace safety. These regulatory exposure threshold
limits are high and are solely based on the thermal heating effect of microwave
radiation. However, many scientists and research publications have shown that other
biological effects exist below the thermal threshold. The question the researchers and
physicians are grappling with is if these effects have negative biological effects? Table 1
provides you with an overview of different international regulatory standards and
recommended precautionary limits by different entities.
Table 1: International Regulatory Threshold Limits, References and Guidelines
Entity
Power Density
Regulatory – FCC/ANSI – USA (800-900 MHz)
Regulatory – Italy, Poland, Hungary, Bulgaria
579,000 nW/cm2
10,000 nW/cm2
4,500 nW/cm2
Regulatory – Switzerland
Recommendation – Ecolog Hannover, Germany (2003)
300 nW/cm2
Recommendation – Salzburg Resolution, Austria (2000)
100 nW/cm2
Recommendation – STOA – EU Parliament (2001)
10 nW/cm2
0.5 – 2 nW/cm2
Average range in metropolitan areas
Background levels in residential areas
0.05 -0.5 nW/cm2
Necessary for cellular phone reception
0.0001 nW/cm2
THE BIOINITIATIVE REPORT
About a year ago, an international working group of
scientists, researchers and public health policy
professionals, The BioInitiative Working Group, has
released its report on electromagnetic fields (EMF) and
health. It raises serious concerns about the safety of
existing public limits that regulate how much EMF is
allowable from power lines, cell phones, and many other
sources of EMF exposure in daily life.
Public health expert and co-editor of the report, Dr.
David Carpenter, Director, Institute for Health and the
Environment at the University of Albany, New York
asserts: "This report stands as a wake-up call that longterm exposure to some kinds of EMF may cause serious
health effects. Good public health planning is needed
now to prevent cancers and neurological diseases linked to exposure to power lines and
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IAQA 2009 Annual Conference Ft. Worth
How “Green” is your Cordless Phone
other sources of EMF. We need to educate people and our decision-makers that,
business as usual, is unacceptable".
The Working Group conducted a comprehensive meta analysis of existing research,
and found that a significant number of studies have shown potential effects such as
increased and altered cell proliferation, influences on hormones, heart, circulatory, and
nervous systems. The Working Group recommends prudent avoidance of excessive
EMF’s. Table 2 outlines the suggested exposure guidelines.
Table 2: BioInitiative Report Guideline Vales
Fields
Location
Value
EMF
Homes and Schools
<1 mG
EMF
<2 mG
RF
Other Buildings
Outside
<100 nW/cm²
RF
Inside
<10 nW/cm²
You can obtain a copy of the BioInitiative Report by downloading it from the following
website www.bioinitiative.org .
HISTORIC TIMELINE
Let’s have a brief look at the development of phone communication equipment and the
current state of the industry. We started with the wired phone lines which are
disappearing rapidly. This trend is very much supported by the service providers for cost
and profit considerations.
Communications devise during
the author’s childhood
Rotary phone with wired phone lines
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IAQA 2009 Annual Conference Ft. Worth
How “Green” is your Cordless Phone
Analog cordless phone
Digital Revolution
Digital cordless phone
Table 3 outlines the historical chronology of cordless phones, their technology,
frequencies and radiation exposure effect.
Table3: Cordless Phone Technologies, Frequencies and Radiation level
Technology
Frequency
Emissions During Stand-by
Wired
DC
No
Analog
400 MHz
No
Digital
915 MHz
No
ISM Band
2.4 GHz
Yes/No
ISM Band
5.8 GHz
Yes/No
DECT 6
1.9 GHz
Yes
The problem with many of the current cordless phones is the fact that the base station is
sending signals (RF radiation) non-stop, 24 hours a day without being in use (stand-by
mode). This effect raises the RF exposure to individuals in buildings significantly.
MEASUREMENTS OF 4 DIFFERENT CORDLESS PHONES
The author purchased four different types of cordless phones currently on the shelves of
all major electronic warehouses. Random samples of different technology systems were
selected. A spectrum analyzer (Rhode & Schwarz FSH3), a directional logarithmic
periodic antenna (Schwarzbeck UKPL 9140) and a high frequency meter (Gigahertz
HFW 35C) were used to conduct the testing.
Measurements were conducted at about a 3 feet distance (1 meter) from the base
station and the handheld devices with the unit in use and in stand-by mode. The
following table identifies the technology system, frequencies and the radiation levels.
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IAQA 2009 Annual Conference Ft. Worth
How “Green” is your Cordless Phone
Table 4: Measurement Results of 4 Cordless Phones
System
Name/Model
Frequency range
DECT 6.0
Panasonic
KX-TG6311S
Base: 1.9 GHz
Handheld 1.9 GHz
5.8 GHz FHSS
Panasonic
KX-TG4321B
Base: 5.8 GHz
Handheld: 5.8 GHZ
5.8 GHz DSS
Vtech
CS5111-2
Base: 0.9 GHz
Handdeld: 5.8 GHz
5.8 GHz analog
GE
25922FE1-A
Base: 5.8 GHz
Handheld 0.9 GHz
Permanent
transmission
Yes
No
Yes
No
No
No
No
No
Power density
nW/cm²
200
200
200
200
50
20
2
20
The results show that the 5.8 GHz DSS and analog technologies power the base station
off while in stand-by mode and create low exposures during use. Therefore, knowledge
of the fields and technology systems are helpful in selecting a cordless phone to create
low EMF environments, i.e. a “greener” building.
Another Phone Measurement
A different type of digital 2.4 GHz cordless phone was placed on a workstation and
measurements were made at different distances from the base station with the phone
not in use (stand-by mode).
Table 5: Power Density Levels of a Cordless Phone Base Station
Distance
Power Density
1 foot
40,500 µW/cm2
20 inches
3 feet
14,600 µW/cm2
3,600 µW/cm2
6.5 feet
910 µW/cm2
Case Study
A client is concerned about the installation of a new cellular base station to be erected
on the roof of a recreation center across the street from their house. The author was
asked to assess the home prior to the installation. Table 6 shows the testing results and
their sources.
Table 6: Measurement Results for Power Density in nW/cm2 from different Sources
Location
Family room
800-900 MHz
Cellular Phone Band
1.8-1.9 GHz
Cellular PCS Band
2.4 GHz
cordless Phone
Total
0.1 nW/cm2
0.1 nW/cm2
493 nW/cm2
493.2
The 2,4 GHz was the single source creating high RF radiation in the room.
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IAQA 2009 Annual Conference Ft. Worth
How “Green” is your Cordless Phone
GREEN RATINGS SYSTEMS
Most of the current DECT 6 and 5.8 GHz phones carry the EPA Energy Star rating.
Obviously, this rating is not related to RF emissions. The DECT manufacturers have
created two kinds of RF reduction methods for their phones for the European market.

“Radiation Reduced” units which power down but do not totally switch off while in
stand-by mode (phone not in use)

“Low Radiation” units which turn the base station off when the phone is not in use
The types of phones were introduced to address customer concerns and consumer
demand.
The German Federal Department for Radiation Safety (Bundesamt für Strahlenschutz)
and the Radiation Protection Commission (Strahlenschutzkommission) have the
following recommendation criteria for “Low Radiation” labeled phones.

Base station to power off or create a 100,000 fold reduction of transmission power
during stand-by mode

Demand selective transmission power adjustments for handheld unit

Demand selective transmission power adjustments for base station

Plug for headset on handheld unit

Regulation of the transmission distance
Listed below is the EMF/RF rating systems for phones proposed by the German indoor
environmental associations.

Wired phone without magnet in speaker (piezo electric technology)

Regular wired phones
!
Analog cordless phones
!!
Digital phones which power off base station in stand-by mode
!!!
DECT phones which power off or provide 100,000 fold reduction at base station
in stand-by mode
!!!!
DECT phones which power down but by a factor of less than 100,000
!!!!!
DECT phones which do not power down or turn off in stand-by mode
Unfortunately, most indoor environmental consultants in the Untied Sated are not even
aware of these EMF and RF issues. With this lack of awareness, manufactures have
not been confronted with a demand to provide low RF DECT phones in the US.
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IAQA 2009 Annual Conference Ft. Worth
How “Green” is your Cordless Phone
CONCLUSION
Our electromagnetic environment has significantly changed over the last decade. New
technologies and the wireless world can expose us to unknown quantities of high
frequency electromagnetic radiation.
Small household items, such as cordless phones, can become a significant source of
RF radiation in indoor environments. The IESO is currently drafting an EMF
measurement standard to be published as an ANSI Standard. Therefore, it is important
that indoor environmental professionals, IAQA members and the IAQ industry be aware,
familiar and able to assist their customers on EMF/RF issues. A “green” building should
also be a low EMF/RF building to provide a healthy habitat. Alternative low emission
technology is available to replace higher emission devices. These parameters should be
part of a “green” building specification and should be evaluated when buildingassociated illnesses are investigated.
Peter Sierck, CIEC, CMC, CMRS
Principal / Industrial Hygienist
ET&T
5431 Avenida Encinas, Suite F
Carlsbad, CA 92008
Tel: 760-804-9400
PSierck@ETandT.com
www.ETandT.com
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